Work will be continued on the isolation and structure determination of a factor from soy-peptone which is required for the axenic culture of the free-living nematode, Caenorhabditis briggsae. After treatment on Dowex-50 and Bio-Gel P-2, a fraction is obtained which supports growth of the organism in defined medium which contains hemin instead of the usual myoglobin or cytochrome c. The active component appears to consist of one or more small peptides. The nature of the sharp reduction in the enzyme activity of glycerophosphate dehydrogenase which occurs when C. briggsae is placed in buffer instead of growth medium, will be investigated. The loss of enzyme activity may be due to repression, alteration or allosteric modification. Hexokinase, glucose-6-phosphate dehydrogenase and fructose-1,6-diphosphatase, which also show large changes in activities, will also be investigated. These changes in activities, will also be investigated. These changes are related to the fact that in "whole" medium, the organisms excrete mostly glycerol, whereas in buffer, the predominant excretion product is glucose. Improvement of a cell-free preparation from C. briggsae which synthesizes proteins, will be undertaken. Trypsin and chymotrypsin will be further purified and their properties determined.